1. Field of the Invention
The present invention relates to a device for sensing the pressure in a pressurized container containing a pressure medium mixed with a solid particulate material or liquid droplets which could block the tube means through which the pressure sensing is effected.
If the pressure in a container is to be sensed (e.g. measured), a pressure measuring means is normally connected to the container, often by means of a conduit which may in certain cases be long and which it is normally desired to maintain of rather narrow bore. If then the pressure medium in the container--it may be a fluid or a gas or air--is mixed with fine particles of foreign matter, for example dust or sludge, there is a constant risk of these particles entering the conduit to the pressure measuring means and blocking it. This will jeopardize the result of the measurement.
2. Description of the Prior Art
In certain cases entry of foreign matter into the conduit can be prevented by filters or traps which, however, are not always satisfactory, especially not if the pressure medium and its entrained particles are in powerful motion or have a high temperature. Another prior art method employs a continuous or regular purging of the conduit leading to the pressure measuring means. In this case, some suitable blowing agent is used for the purging, which is supplied to the plant using a special system. The systems proposed so far, however, have not proved to be satisfactory. During continuous purging, an error in pressure measurement occurs because of the pressure increase in the tube from the blowing agent, whereas periodic blowing may be unreliable. In both cases, the prior art systems are complicated and expensive.